Suture Pull-out Strength Research Articles

The effect of repeated freezing and thawing on the suture pull-out strength in equine arytenoid and cricoid cartilages.

To assess the effect of repeated freezing and thawing on the suture pull-out strength in arytenoid and cricoid cartilages subjected to the laryngoplasty (LP) procedure. Ex vivo experimental study. Ten grossly normal equine cadaveric larynges. Bilateral LP constructs were created using a standard LP technique. One hemilarynx was randomly allocated to the single freeze and thaw group and the other allocated to the repeated freeze and thaw (3 complete cycles) group. The suture ends of each LP construct were attached to a load frame and subjected to monotonic loading until construct failure. Mean load (N) and displacement (mm) at LP construct failure were compared between groups. All LP constructs failed by suture pull through the arytenoid cartilage. The mean load at failure was similar between groups (118.9 ± 25.5N in the single freeze and thaw group and 113.4 ± 20.5N in the repeated freeze and thaw group, P=.62). The mean displacement at failure was similar between groups (54.4 ± 15.1 mm in the single freeze and thaw group and 54.4 ± 15.4 mm in the repeated freeze and thaw group, P=.99). Repeated freezing and thawing did not affect the suture pullout strength of the arytenoid and cricoid cartilages. Laryngeal specimens that have been subjected to repeated freezing and thawing can be utilized in the experimental evaluation of LP procedures because there is no alteration of the suture pull-out strength of the relevant cartilages.

Evaluating Pull-Out Strength of Barbed Suture In Vitro by Using Porcine Tissue and Polydimethylsiloxane (PDMS).

Using barbed thread lifting for facial rejuvenation has become popular these days due to its minimally invasive procedures with reduced complications. However, only limited studies regarding its mechanical properties for face suspension were published. The aim of this study was to evaluate suture-holding ability regarding its facelift property, and different specimens were tested in order to establish an in vitro model. Fresh porcine tissue and the synthetic material polydimethylsiloxane (PDMS) were selected to simulate human skin for evaluating barbed suture pull-out strength by the universal material testing machine. The results showed that the pull-out strength of barbs between different porcine tissues varied without consistency. By contrast, PDMS (30:1) showed more consistent pull-out strength in each testing, and the average maximum load force was close to porcine tissue. Furthermore, after submerging barbed sutures in PBS for 0 days (T0), 7 days (T7) and 14 days (T14), a trend of decreased average maximum load force, displacement and force of 1.5 mm/2 mm/3 mm displacement could be detected by in vitro testing with PDMS (30:1). These results provide support for using PDMS (30:1) to evaluate suture pull-out strength and holding/lifting capacities in vitro to obtain consistent and objective information for evaluating substantial equivalence of devices. The established in vitro method could be used for the future development of barbed thread lifting technology.

Porous membranes of quaternized chitosan composited with strontium-based nanobioceramic for periodontal tissue regeneration.

This report demonstrates the development of a degradable quaternary ammonium derivative of chitosan (QC) composited with strontium-containing nanoapatite (SA) for bioactivity. The material was made as porous membrane by solution casting and freeze drying, for guided tissue regeneration (GTR) applications. The micromorphology, tensile strength, suture pull-out strength, degradation (in vitro, in phosphate buffered saline), and cytocompatibility (using human periodontal ligament cells) were tested to investigate the effect of derivatization and SA addition. The porosity of the membranes increased with increasing SA content and so did the tensile strength and the degradation. The suture pull-out strength, however, showed a decrease. The cell culture evaluation endorsed biocompatibility. The composite with 1.5mg SA per 1mL QC was found to have optimal qualities for GTR applications.

PD32-05 COMPARISON OF HEAVY WEIGHT VERSUS LIGHT WEIGHT WIDE PORE POLYPROPYLENE MESH FOR ROBOTIC SACROCOLPOPEXY USING FOUR MESHES AND 351 CASES

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Pelvic Prolapse (PD32)1 Sep 2021PD32-05 COMPARISON OF HEAVY WEIGHT VERSUS LIGHT WEIGHT WIDE PORE POLYPROPYLENE MESH FOR ROBOTIC SACROCOLPOPEXY USING FOUR MESHES AND 351 CASES Cassandra Schuster, Maximilian Carey, and Robert Carey Cassandra SchusterCassandra Schuster More articles by this author , Maximilian CareyMaximilian Carey More articles by this author , and Robert CareyRobert Carey More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002033.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: All FDA approved wide pore polypropylene Y-mesh grafts available for robotic sacrocolpopexy have variance in the mesh weight, pore size, thickness, surface area ratio and suture pull out strengths. In this study we evaluated results observed for robotic sacrocolpopexy performed with four separate wide pore polypropylene Y meshes that differ markedly in their physical properties. METHODS: Data is collected from an IRB approved prospectively maintained retrospective database of robotic sacrocolpopexy cases performed at an 836 bed tertiary care hospital by a single surgeon. Using analysis matched for covariates of BMI, prolapse stage and previous attempts at repair, We evaluated whether the weight of the Y-mesh influenced the anatomic outcome and rate of de novo SUI at mean 46 month follow-up. RESULTS: Between 2011 and 2020, a total of 351 patients underwent robotic sacrocolpopexy for POP-Q Stage IV VVP. The cases were divided between 4 different mesh materials (n=50, 50, 100, and 151) in patients undergoing repair. The mesh material varied from the heaviest mesh weight (52 g/m2, 527 microns thick, and a suture pull out strength of 18.3 N) to the lightest weight mesh (25 g/m2, 200 microns thick, and suture pull out strength of 23.3 N). At mean 46 month follow-up, anatomic success for apical prolapse was 100% and there was no difference in the rates of Grade 2 or less anterior or posterior prolase in each group (4%). De novo SUI was found in 10% patients in the heaviest mesh group and in 8% of patients in the lighter mesh groups. All de novo SUI patients did not have a mid urethral sling, MUS, placed at the time of the procedure. There was one mesh erosion in the light weight mesh group in a salvage patient that underwent concomitant pre-existing mesh removal at the time of surgery. CONCLUSIONS: Although the two Y-meshes are markedly different in their weight, surface area, thickness and suture pullout strength, there was no observed significant difference in the anatomic success of repair, the rate of de novo stress urinary incontinence or mesh erosion. The rates of de novo SUI seen in this study, have led us to perform a MUS procedure at the time of sacrocolpopexy for all Grade IV prolapse patients. Source of Funding: none © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e546-e546 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Cassandra Schuster More articles by this author Maximilian Carey More articles by this author Robert Carey More articles by this author Expand All Advertisement Loading ...

Locating the rotator cable during subacromial arthroscopy: bursal- and articular-sided anatomy.

The rotator cable (RCa) is an important articular-sided structure of the cuff capsular complex that helps prevent suture pull out during rotator cuff repairs (RCRs) and plays a role in force transmission. Yet, the RCa cannot be located during bursal-sided RCRs. The purpose of this study is to develop a method to locate the RCa in the subacromial space and compare its bursal- and articular-sided dimensions. In 20 fresh-frozen cadaveric specimens, the RCa was found from the articular side, outlined with stitches, and then evaluated from the bursal side using an easily identifiable reference point, the intersection of a line bisecting the supraspinatus (SS) tendon and posterior SS myotendinous junction (MTJ). Four bursal-sided lengths were measured on the SS-bisecting line as well as the RCa's outside anteroposterior base. For the articular-sided measurements, the rotator cuff capsular complex was detached from bone and optically scanned creating 3D solid models. Using the 3D models, 4 articular-sided lengths were made, including the RCa's inside and outside anteroposterior base. The RCa's medial arch was located 9.9 ± 5.6 mm from the reference point in 10 intact specimens and 4.1 ± 2.4 mm in 10 torn specimens (P = .007). The RCa's width was 10.9 ± 2.1 mm, and the distance from the lateral edge of the RCa to the lateral SS insertion was 13.9 ± 4.8 mm. The bursal- and articular-sided outside anteroposterior base measured 48.1 ± 6.4 mm and 49.6 ± 6.5 mm, respectively (P = .268). The average inside anteroposterior base measurement was 37.3 ± 5.9 mm. The medial arch of the RCa can be reliably located during subacromial arthroscopy using the reference point, analogous to the posterior SS MTJ. The RCa is located 10 mm in intact and 4 mm in torn tendons (P = .007) from the posterior SS MTJ. If the above 6-mm shift in location of the RCa is not taken into consideration during rotator cuff suture placement, it could negatively affect time zero repair strength. The inside anteroposterior base of the RCa measures on average 37 mm; therefore, rotator cuff tears measuring >37 mm are at risk of rupturing part or all of the RCa's 2 humeral attachments, which if not recognized and addressed could impact postoperative function.

Mapping of the Inferior Glenohumeral Ligament for Suture Pullout Strength: A Biomechanical Analysis.

Background:Suture pullout during rehabilitation may result in loss of tension in the inferior glenohumeral ligament (IGHL) and contribute to recurrent instability after capsular plication, performed with or without labral repair. To date, the suture pullout strength in the IGHL is not well-documented. This may contribute to recurrent instability.Purpose/Hypothesis:A cadaveric biomechanical study was designed to investigate the suture pullout strength of sutures in the IGHL. We hypothesized that there would be no significant variability of suture pullout strength between specimens and zones. Additionally, we sought to determine the impact of early mobilization on sutures in the IGHL at time zero. We hypothesized that capsular plication sutures would fail under low load.Study Design:Descriptive laboratory study.Methods:Seven fresh-frozen cadaveric shoulders were dissected to isolate the IGHL complex, which was then divided into 18 zones. Sutures in these zones were attached to a linear actuator, and the resistance to suture pullout was recorded. A suture pullout strength map of the IGHL was constructed. These loads were used to calculate the load applied at the hand that would initiate suture pullout in the IGHL.Results:Mean suture pullout strength for all specimens was 61.6 ± 26.1 N. The maximum load found to cause suture pullout through tissue was found to be low, regardless of zone of the IGHL. Calculations suggest that an external rotation force applied to the hand of only 9.6 N may be sufficient to tear capsular sutures at time zero.Conclusion:This study did not provide clear evidence of desirable locations for fixation in the IGHL. However, given the low magnitude of failure loads, the results suggest the timetable for initiation of range-of-motion exercises should be reconsidered to prevent suture pullout through the IGHL.Clinical Relevance:From this biomechanical study, the magnitude of force required to cause suture pullout through the IGHL is met or surpassed by normal postoperative early range-of-motion protocols.

Ultrasound Imaging of the Superficial Fascial System Can Predict the Subcutaneous Strength of Abdominal Tissue Using Mean Gray Value Quantification.

This study is the first to correlate sonographic findings of subcutaneous tissue to structural and biomechanical properties. Precisely sized tissue specimens (59 samples) were collected from five abdominoplasty procedures. A Philips Lumify L12-4 linear array probe, connected to an Android tablet, was used to obtain ultrasound images of the superficial fascial system. A no. 1 Vicryl suture on a CTX needle placed though a needle guide within a three-dimensionally printed template ensured equal bites of subcutaneous tissue across specimens. Suture pull-out strength was measured until failure at a displacement rate of 2.12 mm/second using an Admet MTEST Quattro. Mean gray value for the superficial fascial system in associated ultrasonographic images was quantified by CellProfiler. Superficial fascial system visualization can be accomplished using high-resolution portable ultrasound. Comparing multiple specimens' imaging, interpatient and intrapatient variability of superficial fascial system quantity and structural characteristics are apparent. The superficial fascial system is highly abundant in some patients, but has limited presence in others. Individual-specimen mean gray value and whole-patient mean gray value positively correlated with tissue tensile strength (p = 0.006) and patient-average tissue tensile strength (p = 0.036), respectively. Whole-patient mean gray value accounted for 98.5 percent of the variance seen in patient-average tensile strength, making it a strong predictor for tensile strength. Portable ultrasound and image-processing technology can visualize, quantify, and predict subcutaneous tissue strength of the superficial fascial system. The superficial fascial system quantity correlates with suture tensile strength. Clinically, preoperative superficial fascial system quantification may aid in outcome predictions, manage patient expectations, and potentially lower complication rates. Diagnostic, V.

Fabrication and characterization of novel bacterial cellulose/alginate/gelatin biocomposite film

Hydrogels from bacterial, algal, and animal cells—bacterial cellulose (BC), alginate, and gelatin, respectively—were combined to fabricate a biocomposite film (BCAGG) via an eco-friendly casting technique. In addition, glycerol was added as a plasticizer to improve the elasticity and water absorption capacity of the film. In this study, BC pellicles were simply deconstructed into fibrils suspension and then reconstructed into films with a supplement of alginate, gelatin and glycerol. The physical appearance of fabricated films resembled native BC but possessed improved ductility, enhanced flexibility, higher water uptake ability and better biocompatibility. The film was found to resist tearing under suture pullout strength in a hydrated state. In vitro cytotoxicity tests showed that the film was cytocompatible. A cell study using a human keratinocyte culture demonstrated enhanced cell adhesion, spreading, and proliferation on the BCAGG film compared with BC/alginate film. The BCAGG film therefore has significant potential for use in biomedical applications, particularly in dermal treatment, skin tissue regeneration, and wound healing.

Pectoralis Major Tendon Repair With Acellular Dermal Matrix Augmentation

Pectoralis major tendon tears were historically an uncommon injury, but prevalence has increased with increased awareness and increase in high contact and heavy lifting sports. Operative management of pectoralis tendon tears is complicated by a short tendon stump, frequently requiring sutures to be placed well into the muscle belly, leaving them susceptible to pull-out and failure of the repair. We present a technique of pectoralis major tendon repair augmented by the use of an acellular dermal matrix. Acellular dermal matrices or allografts are used elsewhere in orthopedics and have been proven both clinically and biomechanically to lead to increased suture pull-out strength. This repair technique increases the “effective” length and increases the suture pull-out strength. As a result, patients are allowed to rehabilitate rapidly in the postoperative period and the surgeon can have more confidence in the strength of the repair.

PD17-03 MATCHED PAIR ANALYSIS COMPARING HEAVY WEIGHT VERSUS LIGHTER WEIGHT WIDE PORE POLYPROPYLENE MESH FOR ROBOTIC SACROCOLPOPEXY

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Pelvic Prolapse II1 Apr 2017PD17-03 MATCHED PAIR ANALYSIS COMPARING HEAVY WEIGHT VERSUS LIGHTER WEIGHT WIDE PORE POLYPROPYLENE MESH FOR ROBOTIC SACROCOLPOPEXY Robert Carey, Ali Harris, Maximilian Carey, and Karim Ghazli Robert CareyRobert Carey More articles by this author , Ali HarrisAli Harris More articles by this author , Maximilian CareyMaximilian Carey More articles by this author , and Karim GhazliKarim Ghazli More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.850AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES All FDA approved wide pore polypropylene Y-mesh grafts available for robotic sacrocolpopexy have variance in the mesh weight, pore size, thickness, surface area ratio and suture pull out strengths. In this study we evaluated results observed for robotic sacrocolpopexy performed with two separate wide pore polypropylene Y meshes that differ markedly in their physical properties. METHODS Data is collected from an IRB approved prospectively maintained retrospective database of robotic sacrocolpopexy cases performed at an 836 bed tertiary care hospital by a single surgeon. Using analysis matched for covariates of BMI, POP-Q stage, surgeon, and previous attempts at repair, we evaluated whether the weight of the Y-mesh influenced the anatomic outcome and rate of de novo SUI at two year follow-up. RESULTS Between 2011 and 2016, a total of 175 patients underwent robotic sacrocolpopexy for POP-Q Stage IV VVP. 50 patients undergoing repair with a heavy mesh weight (52 g/m2, 527 microns thick, and a suture pull out strength of 18.3 N) were matched to 50 patients undergoing repair with a lighter weight mesh ( 25 g/m2, 200 microns thick, and suture pull out strength of 23.3 N). At two year follow-up, anatomic success for apical prolapse was 100% and 2 patients (4%) in each group were found to have residual Grade 2 anterior prolapse and 2 patients (4%) in each group found to have Grade 2 posterior prolapse. De novo SUI was found in 5 patients (10%) in the heavy mesh group and 4 patients (8%) in the lighter mesh group. All de novo SUI patients did not have a mid urethral sling, MUS, placed at the time of the procedure. There was one mesh erosion in the light weight mesh group in a salvage patient that underwent concomitant pre-existing mesh removal at the time of surgery. CONCLUSIONS Although the two Y-meshes are markedly different in their weight, surface area, thickness and suture pullout strength, there was no observed significant difference in the anatomic success of repair, the rate of de novo stress urinary incontinence or mesh erosion. The rates of de novo SUI seen in this study, have led us to perform a MUS procedure at the time of sacrocolpopexy for all Grade IV prolapse patients. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e353-e354 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Robert Carey More articles by this author Ali Harris More articles by this author Maximilian Carey More articles by this author Karim Ghazli More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

The Dorsal Intermetatarsal Approach for Plantar Plate and Lateral Collateral Ligament Repair of the Lesser Metatarsophalangeal Joints

Category: Lesser Toes Introduction/Purpose: Access to the plantar plate has been described using either a plantar approach or an extensile dorsal approach that required complete joint destabilization and often a metatarsal osteotomy. Clinical scenarios related to plantar plate tear vary and the pathologies in early stages are frequently limited to unilateral soft tissue structures, a more focused surgical approach deemed appropriate. A novel approach requiring a release of only the lateral collateral ligament and the lateral half of the plantar plate was described and the adequacy of joint exposure was evaluated in a cadaver model. The ability to place a suture through the lateral collateral ligament and the plantar plate were analyzed and validated with pull-out strength. Methods: Nine fresh frozen cadaveric specimens were dissected in a randomized fashion across the 2nd to 4th MTP joints through the intermetatarsal space dorsally. Under distraction, soft tissue was sequentially released including dorsal capsule, lateral collateral ligament, and the lateral half of the plantar plate. Integrity of the extensor tendons, deep transverse intermetatarsal ligament, proximal attachment of the plantar plate, and osseous structures was carefully preserved. The joint exposure was quantified after each step with sizing rods. 2/o non-absorbable sutures were passed into the lateral collateral ligament and the plantar plate using a suture passer; and their pullout strength was measured using a tensiometer. Results: Progressive increase in mean of joint exposure was noted after each step of soft tissue release with the final exposure of 6mm after release of the lateral half of the plantar plate. Joint exposures after a capsulotomy and a lateral collateral release were 3mm and 4mm, respectively. Under distraction, the unilateral release of soft tissue created a lateral opening of the joint while the proximal phalangeal base adducted and medially deviated. Successful suture passage was noted in all specimens with mean pullout strength of 76 N for the lateral collateral ligament and 67 N for the plantar plate. There was a statistically significant (p < 0.01) higher suture pullout strength for the lateral collateral ligament in males when compared to female specimens Conclusion: The dorsal intermetatarsal approached appeared to be feasible for the access to the lateral collateral ligament and the lateral half of the plantar plate. The average joint exposure of 6 mm allowed a quality suture passage by a suture passer in both structures in all specimens without the need of a metatarsal osteotomy.

Tendon Collagen Crosslinking Offers Potential to Improve Suture Pullout in Rotator Cuff Repair: An Ex Vivo Sheep Study.

The suture-tendon interface is often the weakest link in tendon to bone repair of massive rotator cuff tears. Genipin is a low-toxicity collagen crosslinker derived from the gardenia fruit that has been shown to augment collagen tissue strength and mechanically arrest tendon-tear progression. The purpose of the current study was to evaluate whether genipin crosslinking can sufficiently augment the suture-tendon interface to improve suture pullout strength using simple single-loop sutures and the modified Mason-Allen technique. The study also aimed to assess whether time of genipin treatment is a relevant factor in efficacy. In an ex vivo (cadaveric) sheep rotator cuff tendon model, a total of 142 suture pullout tests were performed on 32 infraspinatus tendons. Each tendon was prepared with three single-loop stitches. Two groups were pretreated by incubation in genipin solution for either 4 hours or 24 hours. Two corresponding control groups were incubated in phosphate buffered saline for the same periods. The same test protocol was applied to tendons using modified Mason-Allen technique stitch patterns. Each suture was loaded to failure on a universal materials testing machine. Suture pullout force, stiffness, and work to failure were calculated from force-displacement data, and then compared among the groups. Median single-loop pullout force on tendons incubated for 24 hours in genipin yielded an approximately 30% increase in maximum pullout force for single-loop stitches with a median of 73 N (range, 56-114 N) compared with 56 N (range, 40-69 N; difference of medians = 17 N; p = 0.028), with corresponding increases in the required work to failure but not stiffness. Genipin treatment for 4 hours showed no added benefit for suture-pullout behavior (46 N, [range, 35-95 N] versus 45 N, [range, 28-63 N]; difference of medians, 1 N; p = 1). No tested genipin crosslinking conditions indicated benefit for tendons grasped using the modified Mason-Allen technique after 4 hours (162 N, [range, 143-193 N] versus 140 N, [range, 129-151 N]; difference of medians, 22 N; p = 0.114) or after 24 hours of crosslinking (172 N, [range, 42-183 N] versus 164 N [range, 151-180 N]; difference of medians, 8 N; p = 0.886). Exogenous collagen crosslinking in genipin can markedly improve resistance to pullout at the tendon-suture interface for simple stitch patterns while the modified Mason-Allen stitch showed no benefit in an ex vivo animal model. Tendon strength augmentation by genipin pretreatment offers the potential to improve suture retention properties. Future studies are warranted for the development of clinically viable intraoperative delivery strategies and in vivo testing for safety and efficacy.

Porcine collagen membrane for guided bone regeneration: in vitro and in vivo characterization studies

Event Abstract Back to Event Porcine collagen membrane for guided bone regeneration: in vitro and in vivo characterization studies Natsuyo S. Lee1, Hui-Chen Chen1, Debbie Yuen1 and Shu-Tung Li1 1 Collagen Matrix, Inc., Research and Development, United States Introduction: Resorbable collagen-based membranes (RCM) have become the standard of care for guided bone regeneration (GBR) procedures. Depending on the design of the RCM, some are conformable, some have high mechanical strength, and yet some have distinct surface layers that require a direction for placement. We have developed a biomechanically strong, completely conformable single layer porcine collagen membrane (PCM) to satisfy the growing needs of clinicians. PCM was evaluated in vitro and in vivo to demonstrate its capabilities as a barrier membrane for GBR applications. Materials: Peritoneum tissue was cleaned in Triton X-100, rinsed in water, and extracted in acid, base, salt solutions, and alcohols to remove the soluble non-collagenous moieties. The tissue was then treated with purified porcine tendon collagen to convert the fibrous side of the peritoneum to a smooth surface. The treated membrane was crosslinked, sized, packaged, and sterilized. Methods: In Vitro Characterization: SDS-PAGE: SDS-PAGE was performed for collagen typing according to the method of Ramshaw et.al. [1] Hydroxyproline, Elastin, and Desmosine Analyzes: Hydroxyproline and elastin contents in purified peritoneum tissue were determined by the method of Bergman and Loxely [2] and Mecham [3], respectively. Desmosine content in elastin was determined from amino acid analysis. Total collagen content was then calculated based on the data summarized in Table 1. Suture Pull Out Strength: Suture pull-out strength was conducted using a Chatillon mechanical tester at a pulling speed of 2.5cm/min. Conformability: Conformability testing was conducted using standards from the textile industry [4]. Hydrothermal Shrinkage Temperature (Ts): Samples were analyzed using Mettler Toledo DSC. Ts was defined as the onset temperature of the structure change of collagen from triple helix to random coil. In Vivo Intra-Oral Implantation Study: A total of 18 New Zealand White rabbits were used in the study. Two pocket sites at the gum tissue over the maxilla per animal were created and implanted with PCM or a marketed RCM (BioGide, Geistlich) per site. At 4, 8 and 12 weeks, animals were euthanized and explants were collected for histological processing and analysis. Parameters evaluated included implant resorption, new collagen deposition, and host tissue response. Results and Discussion: SDS-PAGE analysis showed that PCM is primarily composed of type I collagen with a minor amount of type III collagen (Fig. 1). From Table 1, the lower hydroxyproline content is consistent with high elastin content present in PCM. High suture pull out strength along with complete conformability allow the membrane to be secured to minimize cell infiltration. The Ts corresponds to the minimal crosslinking of PCM for in vivo stability. The results from the animal study showed that both PCM and BioGide were biocompatible. Both membranes resorbed over time with corresponding new collagen deposition (Fig.2). The estimated complete resorption time for PCM is approximately 12 weeks, about four weeks longer than BioGide (Ts=46oC), consistent with the higher Ts of PCM. Conclusion Results of both the in vitro and in vivo studies provide support that PCM meets the requirements for use as a cell barrier membrane in GBR procedures.

The Effect of 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide Suture Coating on Tendon Repair Strength and Cell Viability in a Canine Model

To determine if impregnating a suture with a cross-linking agent, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), improved suture pull-out strength and cell viability. Canine flexor digitorum profundus tendons were cut in canine zone D, and a single suture loop was placed in each end, with sutures soaked in either saline or an EDC solution with a concentration of 1%, 10%, or 50%. Suture pull-out strength, stiffness, and elongation to failure was determined by pulling the loop until failure. Cytotoxicity of the EDC treatment was evaluated by suspending treated sutures over cultured tenocytes. Mechanical properties for the EDC-treated side were improved over controls when treated with the 10% and 50% EDC solutions. The ratio of dead to live cells was significantly increased at all distances from the suture for the 50% EDC-treated group. Suture treated with a 10% EDC solution provided the best combination of mechanical reinforcement and limited toxicity. Sutures so treated may improve the ability of a tendon repair to sustain early mobilization.

Medial Regeneration Using a Biodegradable Felt as a Scaffold Preserves Integrity and Compliance of a Canine Dissected Aorta

Repair of a dissected aorta involves reattaching the media with synthetic glue and/or reinforcement with nonbiodegradable felt. Late complications specific to each aspect of this procedure have been reported. We attempted to regenerate the media by using biodegradable felt. We created a canine model of descending thoracic aortic dissection and compared 4 modes of aortic repair: biodegradable polyglycolic acid (PGA) felt in the media; PGA with basic fibroblast growth factor (bFGF) in the media; PGA with bFGF in the media plus external reinforcement with expanded polytetrafluoroethylene; and primary suture closure of the dissected lumen (control). Repaired aortic stumps were quantitatively tested for suture pull-out strength. Failure force improved 4-fold in all 3 medial reinforcement groups compared with controls. Additionally, animals were kept alive for histological examination and compliance testing 6 months after repair. Compliance of the aortic wall at the anastomotic sites was not essentially affected in the long term except in the group with concomitant external reinforcement (55.9 ± 4.5% reduction; P<0.05). In this group, elastic fiber in the media and collagen fiber in the adventitia tended to diminish relative to the other groups. Regarding vessel density in the repaired false lumen, this external reinforced group had a significantly decreased number. Histological derangement was not observed in control or medial reinforcement groups. Basic FGF, applied with PGA in the dissected lumen, failed to yield additional modifications in this model. Medial reinforcement provides sufficient augmented strength for aortic surgical repair. Medial regeneration using biodegradable felt as a scaffold preserves histological integrity and compliance in the canine dissected aorta.

Suture pullout strength and in vitro fibroblast and RAW 264.7 monocyte biocompatibility of genipin crosslinked nanofibrous chitosan mats for guided tissue regeneration

Guided tissue regeneration (GTR) is a surgical technique used to direct the formation of bone in the graft space by protecting it with a barrier membrane used to exclude soft tissues during healing. Chitosan has been advocated for GTR applications because of its biocompatibility, degradability, wound healing, and osteogenic properties. In this study, electrospun chitosan membranes, crosslinked with 5 mM or 10 mM geinipin, a natural crosslinker extracted from the gardenia plant, were evaluated for suture pullout strength, crystallinity, and cytocompatibility with normal human dermal fibroblast and TIB 71™ RAW 264.7 monocyte cells. Ultimate suture pullout strength was significantly lower (51-67%) than that of commercially available collagen membranes. Crystallinity of the electrospun chitosan mats decreased upon crosslinking by 14-17% (p = 0.013). The molecular weight of the chitosan polymer was decreased by 75% during the electrospinning process. Uncrosslinked and genipin-crosslinked chitosan mats were cytocompatible and supported fibroblast cell proliferation for 9 days. Uncrosslinked and genipin-crosslinked membranes did not activate monocytes to produce nitric oxide (NO) in vitro in the absence of lipopolysaccharide (LPS). Finally, chitosan membranes inhibited LPS-induced NO production of RAW 264.7 cells by 59-67% as compared to tissue culture plastic and collagen membrane. Improvements are needed in the tear strength of electrospun chitosan membranes for clinical application.

Closure of Mid-Posterior Tenon's Capsule in Enucleation

To evaluate the potential advantages of closing mid-posterior Tenon's capsule during enucleation surgery by comparing its thickness and relative tissue strength with anterior Tenon's capsule. To evaluate surgical outcomes of enucleation using mid-posterior Tenon's capsule closure. This is an experimental laboratory study and retrospective surgical case series. Histologic examination of Tenon's capsule was performed on permanently fixated human orbital specimens. Suture pull-out testing as a measure of tissue strength was performed on anterior and mid-posterior Tenon's capsule in nonfixated human cadaver orbits. A retrospective review of enucleations with primary orbital implant placement performed by the authors between 1998 and 2008 was conducted to determine the surgical outcomes of enucleation using closure of mid-posterior Tenon's capsule. Histologic analysis showed the average thickness of mid-posterior Tenon's capsule to be 121% greater than that of the anterior portion (518 vs. 234 μ, p < 0.001). Suture pull-out strength was 84% higher in mid-posterior versus anterior Tenon's capsule (741 vs. 1298 g, p = 0.016). Of the 103 enucleations performed by the authors (54 with unwrapped silicone implants and 49 with unwrapped porous polyethylene), there were 2 cases (1.9%) of implant extrusion and 1 case (1%) of implant exposure. From a structural and biomechanical standpoint, mid-posterior Tenon's capsule is significantly thicker and stronger than anterior Tenon's capsule, theoretically providing a superior barrier to orbital implant exposure and extrusion after enucleation.

Vaginal mesh grafts and the Food and Drug Administration

Vaginal mesh grafts and the Food and Drug Administration

The effect of tissue culture on suture holding strength and degradation in canine tendon

The purpose of this study was to assess tendon metabolism and suture pull-out strength after simple tendon suture in a tissue culture model. One hundred and twelve flexor digitorum profundus tendons from 28 dogs were cultured for 7, 14, or 21 days with or without a static tensile load. In both groups increased levels of matrix metalloproteinase (MMP) mRNA was noted. Suture pull-out strength did not decrease during tissue culture. While the presence of a static load had no effect on the pull-out strength, it did affect MMP mRNA expression. This tissue culture model could be useful in studying the effect of factors on the tendon-suture interface.

Comparative in vitro biomechanical evaluation of two soft tissue defect products.

A soft tissue defect is often an unavoidable consequence of various surgical procedures or a result of trauma. Recently, intraoperative use of xenograft as a patch to the soft tissue defect has become popular with various products available in the market. In this study, mechanical properties of the OrthADAPTtrade mark Bioimplants (Pegasus Biologics, Irvine, CA), new xenograft products composed of collagen from equine pericardium, were evaluated individually and against an existing bioimplant product. The OrthADAPTtrade mark Bioimplants have three subtypes which differ in the degree of crosslinking of collagen strands. The three products are named as FX, PX, and MX in the order of the degree of collagen crosslinking and likely durability in vivo, with FX most dense in crosslinking and hence most durable. The three subtypes underwent three destructive mechanical tests: tensile strength, suture pull-out strength, and burst strength test. In tensile strength and suture pull-out strength tests, the three products were compared with CuffPatchtrade mark, a similar collagen-based xenograft product from a competing manufacturer. In the burst strength test, the three products were compared with untreated equine pericardium tissue. In tensile strength and suture pull-out strength tests, the products FX and MX were shown to have mechanical properties that were comparable with CuffPatch, while the mechanical strength of PX was significantly inferior to FX and CuffPatch in tensile strength test. In burst strength test, there were no differences in mechanical properties among the three OrthADAPT Bioimplants. This study demonstrates the biomechanical equivalence of OrthADAPT with CuffPatch. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007.